When's the Best Time of Day to Make a Decision?

A study used looked at the decisions chess players made to determine the best time to make them, with surprising results. VasjaKoman/Ken Jacobsen/Getty Images

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Do you make better decisions in the morning or the evening? That might depend on whether you want a quick decision or an accurate one.

Researchers looked at the decision-making behavior of 184 users of the Free Internet Chess Server (FICS) to discover at what time of day players made the best decisions. Chess players — who in this case made around 40 move decisions, in games lasting from three to 15 minutes — are often used in experiments that analyze complex human thinking. The FICS chess game database presented itself as the optimal study tool. With its treasure trove of time-stamped, right and wrong decisions, it allowed researchers to study not just the length of time but also the quality of real-world decision-making behavior at various times of day.

The study published in the journal Cognition showed that whether you're a morning person or not, the most accurate decision-making happens on the early side of the day between 8 a.m. and 1 p.m.

However, even though morning decisions were most accurate, those also took the longest to make. And that's a liability in a time-limited chess game. As the day wore on, the chess players' decision-making sped up but accuracy slumped. Ultimately the time of day had no effect on the players' scores, as decision speed and accuracy canceled each other out.

"In some way these two variables are compensating to maintain the performance throughout the day," says the study's lead author, Maria Juliana Leone, a postdoctoral fellow at the Integrated Neuroscience Lab at the Universidad Torcuato Di Tella in Buenos Aires, Argentina.

Leone suspected it was more than growing tiredness as a day waned that affected players' speed of decision-making. Groups of players were observed playing more games at certain times than others. She thought the gamers' chronotypes might be playing a role. These are classifications based on which of a day's 24 hours a person chooses for sleep. Subjects were asked to complete a Morningness-Eveningness questionnaire to determine whether they tended to be larks, who prefer to rise early, or owls, who like to sleep late.

Leone's research showed that both larks and owls played the most chess games at about the same hours since awakening. (Even though owls would get started later than larks, the number of games would end up being the same.) Surprisingly, the decision-making pattern was the same for both groups — it got slower as the day progressed. However, the larks slowed down the most.

So how can we put the findings of this study to concrete use? "If we know that during the morning we are slower but our decisions are more accurate and during the afternoon we know that our decisions will be faster but less accurate, we can decide when to make some important decisions according to what is important for that decision in particular," says Leone, herself a chess champion. "Maybe we need to prioritize the time or the quality. If we need to make a decision faster, maybe it's better to make that decision in the afternoon.

Leone took the chronotype questionnaire and found she was halfway between the morning larks and the night owls. She therefore tries to schedule intense work tasks closer to the middle of the day. But with all the daily demands of the work, she hasn't yet managed to divide and schedule her decision-making for optimal results. "It is not easy for me either," she says.

Now That's Interesting

One of the only other examinations of how time of day influences the quality of decision-making was a 2011 study of judges. Decisions were 65 percent favorable right after a meal, but almost 100 percent unfavorable just before. So plan, if you can, to get your verdict only from a judge on a full stomach.